I think it's very strange that the king was not present in the most important trial in the recent history of Westeros and nobody seemed to care. Why did Margaery only very late ask about her spouse? What about the High Sparrow, had he also forgotten about the second pillar of the empire? I wouldn't have thought that Loras' trial could even begin without the presence of the king. As seen it was necessary for Tommen to announce it and declare the changing of the rules (no trial by combat). So how is is possible that no one seems to care about his absence during the trial?
Is there something I missed about the Westerosi judicial system or is this just a huge plothole?